Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(Allah loveth not the utterance of harsh speech) verbal abuse (save by one who has been wronged) in this case, he is permitted to make supplications; it is also said that this means: Allah does not love the utterance of harsh speech even from one who has been wronged. (Allah is ever Hearer) of the supplication of the person who has been wronged, (Knower) of the punishment of the transgressor. This verse was revealed about Abu Bakr who was verbally abused by a man.
God does not like the utterance of evil words out loud, by any person, that is to say, He will punish him for it, unless a person has been wronged, in which case He would not punish him for uttering it out loud, when he is informing [others] of the wrong done to him by the wrong-doer or summoning [them] against him. God is ever Hearer, of what is said, Knower, of what is done.
(Allah does not like that the evil should be uttered in public) "Allah does not like that any one should invoke Him against anyone else, unless one was wronged. In this case, Allah allows one to invoke Him against whoever wronged him. Hence Allah's statement,
إَلاَّ مَن ظَلَمَ
(except by him who has been wronged.) Yet, it is better for one if he observes patience.'' Al-Hasan Al-Basri commented, "One should not invoke Allah (for curses) against whoever wronged him. Rather, he should supplicate, `O Allah! Help me against him and take my right from him.''' In another narration, Al-Hasan said, "Allah has allowed one to invoke Him against whoever wronged him without transgressing the limits.'' `Abdul-Karim bin Malik Al-Jazari said about this Ayah; "When a man curses you, you could curse him in retaliation. But if he lies about you, you may not lie about him.
(Whether you disclose a good deed, or conceal it, or pardon an evil; verily, Allah is Ever Pardoning, All-Powerful.) Meaning when you, mankind, admit to a good favor done to you, or conceal it, and forgive those who wrong you, then this will bring you closer to Allah and increase your reward with Him. Among Allah's attributes is that He forgives and pardons His servants, although He is able to punish them. Hence Allah's statement,
فَإِنَّ اللَّهَ كَانَ عَفُوّاً قَدِيراً
(Verily, Allah is Ever Pardoning, All-Powerful.) It was reported that some of the angels who carry Allah's Throne praise Him saying, "All praise is due to You for Your forbearing even though You have perfect knowledge (in all evil committed).'' Some of them supplicate, "All praise is due to You for Your forgiving even though You have perfect ability (to punish).'' An authentic Hadith states,
(No charity shall ever decrease wealth, and Allah will only increase the honor of a servant who pardons, and he who is humble for Allah's sake, then Allah will elevate his grade.)
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
The moral instructions contained in this verse are of the highest standard. The Muslims have been taught to practice virtue or at least to show forbearance even in the face of. revocation. At the time of its revelation, the hypocrites, the Jews and the idolaters were all engaged in opposing Islam by all possible means and were maltreating its followers in every conceivable way. Therefore it was but natural that the Muslims should be tilled with feelings of anger and hatred. When Allah noticed the storm of emotion rising in their hearts, he warned them that He did not like that they give vent to their feelings, though they were wronged and therefore justified, if in retaliation they gave expression to their bitter feelings. They were taught that they, as Muslims, were expected to go on doing good openly and secretly or at least refrain from doing evil for evil. They were instructed, "You should try to mold your character after that of your Allah, Who is so Forbearing that He does not withhold His provisions even from the most wicked culprits and shows forbearance to the most sinful offenders. You should, therefore, have a big heart and show forbearance even in the most critical and provocative situations."
God does not like the utterance of evil words out loud unless a person has been wronged. God is ever Hearer Knower. What a person who has been wronged says about the one who has wronged him is not evil in the true sense of the word by the permission of God but it is nonetheless a good thing to let the matter drop. God most high has said “For the requital of an evil is an evil deed like it” [42:40] so requital is not an evil deed. [But whoever pardons and reconciles his reward will be with God. Truly He does not like wrongdoers] [42:40]. It is said that anyone who knows that his Protector hears is ashamed to give free voice to the urgings of his lower self. It is said that evil words out loud are what you hear within yourself [when] you think ill thoughts about others. The elect take responsibility in their inward thoughts for that which if heard [out loud] from ordinary people might be held against them. Unless illā a person has been wronged: Some say [this means] “not even wa-lā the one who has been wronged.” Others say its meaning is this: “But wa-lakinna a person who has been wronged” has the right to mention the one who has intentionally wronged him. It is said that those who do not prefer praise of the Real madḥ al-ḥaqq over defaming one's fellow creatures qadḥ al-khalq have been cheated of the present moment. It is said that those who look to created beings with the eye of connecting to the Real [see] that they are servants of God [and] will speak no ill of them. A man says to his companion “Out of respect for you I will bear the lowliest service to you even beyond that which I would bear for my son.” When there is commitment like this between human beings how much more worthy is the servant's regard for refined behavior adab between him and His Protector! It is said that God does not like the utterance of evil words out loud among ordinary people nor does He like that in the inward thoughts of the elect. It is said that the utterance of evil words out loud among ordinary people is their description of God in ways [for which they] have no permission or divine sanction.
The utterance of evil words out loud is describing your fellow creatures in ways that the law does not permit. [It is] describing the Real as He cannot be described so that you will be lying regarding Him. [It is also] describing any deficiencies of the elect even if you are being sincere. God is ever Hearer Knower: Hearer of what you say Knower of your defects. It means “do not say of others that which you know is the same in you.” It is said [this means] Hearer of what you say Knower of the blamelessness of the one you defame. There is a threat in [the verse] to the defamer on behalf of the one who is innocent of what he has been accused. It is said that Hearer [is addressed to] “O you who wrongs” [and] Knower [is addressed to] “O you who has been wronged.” This is a threat to these and good news for those.
(Allah loveth not the utterance of harsh speech…) [4:148]. Said Mujahid: “One man sought hospitality with some people. However, because they did not show him proper hospitality, he complained about them. And so this verse was revealed, giving him dispensation to complain”.